Multi-purpose sheet metal folding press, punch, and nibbling machine

ABSTRACT

A brake press or the like having an operating shaft with a crank thereon and a connecting rod between the crank and the movable die holder. The connecting rod is articulated at a knee between its ends, and having a hydraulic cylinder operatively connected to the knee of the connecting rod to impart primary motion to the movable die holder. Rotation of the operating shaft imparts secondary motion to the die holder. Adjustable stop means are provided to limit primary motion.

UnitedjStates Patent [191 Bridges MULTI-PURPO SE SHEET METAL FOLDING PRESS, PUNCH, AND NIBBLING MACHINE [75] Inventor: Denis Richard Bridges, Wingfield, South Australia,

[73 Assigneei B szl l Products Proprietary Limited,

Wingfield, South Australia, I Australia a [22] Filed: Aug. 11, 1971 [21] Appl. No.: 170,695

[30] Foreign Application Priority Data Aug. 20, 1970 Australia 2268 [52] US. Cl. 72/441, 72/451 [51] Int. Cl B21j 9/21) [58] Field of Search 72/450, 389, 452, 72/451, 453, 441, 461

[56] References Cited UNITED STATES PATENTS 1,956.658 5/1934 Schmidt 72/451 2,237,170 4/1941 Williamson.... 681,873 9/1901 Carney 3,222,913 12/1965 Leopold 3,518,869 7/1970 Forichon 72/453 2,797,724 7/1957 Walldow 72/441 3,126,045 3/1964 Streit 72/441 FOREIGN PATENTS OR APPLICATIONS 746,719 8/1944 Germany 72/451 Primary Examiner-Charles W. Lanham Assistant Examiner-Gene P. Crosby Attorney-Charles W. Rummler et a1.

' 1 [57] ABSTRACT A brake press or the like having an operating shaft with a crank thereon and a connecting rod between the crank and the movable die holder. The connecting rod is articulated at a knee between its ends, and having a hydraulic cylinder operatively connected to the knee of the connecting rod to impart primary motion to the movable die holder. Rotation of the operating shaft imparts secondary motion to the die holder. Adjustable stop means are provided to limit primary motion.

14 Claims, 8 Drawing Figures PATENTED 91975 SHEET 10F 6 PATENTEUIIBT elm 3,763,689

SHEET u 0F 6 MULTI-PURPOSE SHEET METAL FOLDING PRESS, PUNCH, AND NIBBLING MACHINE This invention relates to improvements in presses of the type used for folding of sheet metal, and also to presses which may be used for punching or for nibbling of sheet metal.

The conventional press used for folding sheet metal is usually operated by a crank and connecting rod mechanism providing a constant stroke; any variation in metal thickness or angle of fold being accommodated by adjusting the height of the stationary or movable bolster.

It is an object of the invention to produce a press operated by a crank and connecting rod mechanism wherein the terminal position of the moving die, at the end of the working stroke, in relation to the bolster can be simply and easily adjusted.

In one of its forms the invention consists of a press comprising a frame, a bolster on the frame, a movable die holder, guide means between the movable die holder and the frame guiding the movable die holder for rectilinear movement on the frame, an operating shaft, drive means connected to the operating shaft, said drive means comprising a clutch for imparting intermittent rotary motion to the operating shaft, a crank on the operating shaft, and connecting means coupling the crank to the movable die holder to impart thereto said rectilinear movement, said connecting means comprising a connecting rod journalled on said crank, a link, a first pivot pin pivotally connecting one end of said link to said connecting rod, a second pivot pin connecting the other end of said link to the movable die holder, and a hydraulic cylinder operatively connecting the frame and said connecting means, so constructed and arranged that operationof said hydraulic cylinder imparts a primary motion to the movable die holder by varying the angular relationship between the connecting rod and link; and rotation of said shaft imparts a secondary motion thereto through the crank.

By incorporating the feature of the hydraulic cylinder for effecting primary motion, it becomes a relatively simple matter to adjust the terminal position of the moving die in relation to the bolster (the shut height), since the secondary motion due to the rotation of the operating shaft is essentially constant. However if the primary motion is varied, theshut height will vary accordingly and by this means metals of varying thickness can be folded to the same angle, or metals of the same thickness can be folded to differing angles, merely by adjusting the primary movement.

In order to achieve this, this invention in another form includes among its further features, screw threaded stop means carried on the frame, and an abutment member on the connecting means engageable against the screw threaded stop means to thereby limit the primary motion.

While the hydraulic cylinder can for example be connected to respective said first pivot pin, such an arrangement is clumsy for control of the hydraulic circuit and in order to avoid working of the hydraulic cylinder during the secondary motion imparted by the operating shaft, the invention in another form includes a guide arm pivotally supported by the operating shaft, said abutment member being on the guide arm, and the cylinder being coupled to the guide arm, the guide arm being comprised in said connecting means.

The guide arm may contain a slot having parallel walls forming a guide track, and a roller carried by said first pivot pin engages the tracks.

It is frequently necessary to carry out a series of folds on the same sheet, each fold requiring a stroke of different length. The usual method is to set up the machine for the first fold, complete a batch, and re-set the machine for the next fold, thus handling the sheet successively for each fold.

It is a further object of the invention to produce a machine which can be programmed to folda'sheet several times, the stroke being automatically varied between folds to a predetermined pattern.

In another of its forms the invention includes a plate carried on the frame, means on the frame supporting the plate for rotation about an axis, and a plurality of said screw I threaded stop means circumferentially spaced on the plate on a pitch circle having said axis as its centre.

The invention comprises a press having a frame, a bolster on the frame, a movable die holder, guide means between the movable die holder and the frame guiding the movable die holder for rectilinear movement on the frame, an operating shaft, and drive means connected to the operating shaft; said drive means comprising a clutch for imparting intermittent rotary motion to the operating shaft, a crank on the operating shaft, and connecting means coupling the crank to the movable die holder to impart thereto said rectilinear movement; said connecting means comprising a connecting rod journaled on said crank, a link, a first pivot pin pivotally connecting one end of said link to the connecting rod, a second pivot pin connecting the other end of said link to the movable die holder, stop means carried on the frame, and an abutment member on said connecting means engagable against the stop means to thereby limit primary motion, and a hydraulic cylinder operatively connecting the frameand said connecting means; said connecting means being so constructed and arranged that operation of said hydraulic cylinder imparts primary motion to the movable die holder and rotation of said shaft imparts secondary motion thereto.

An embodiment of the invention is described hereunder in some detail with reference to and is illustrated in the accompanying drawings in which:

FIG. 1 is a perspective view of a press,

FIG. 2 is a section taken on plane 22-2-2 of FIG.

FIG. 3 is a section taken on line 3-3 of FIG. 2 but drawn to an enlarged scale,

FIG. 4 is a fragmentary section taken on line4-4 of FIG. 2,

FIG. 5 is a fragmentary section taken on line 55 of FIG. 4,

FIG. 6 is a fragmentary view of one of the end plates of the press and showing the foot pedal and control switch arrangement,

FIG. 7 is a schematic view of the hydraulic and electric circuits and FIG. 8 is a fragmentary sectional view showing the drive means.

In this embodiment a press 10 comprises a frame 11 having a bolster l2 thereon, the frame 11 being provided with guide means 14 which guide a die holder 15 for vertical rectilinear movement on the frame.

The frame is provided with drive means coupled to gears 17 on each end of the operating shaft 18, the gears 17 being housed in gear housings 19. The drive means comprises motor 121, belt drive 122, pinions 123-124, and clutch means 125 which are incorporated in the driving of the gear 17, the clutch means and drive means being in accordance with known art. The clutch means however is operated by a clutch link 20 illustrated on FIG. 8. The clutch is arranged in the conventional manner, that is, for imparting intermittent rotary motion to the operating shaft 18.

The operating shaft 18 is provided with cranks, in this embodiment the cranks being eccentrics 22, and connecting means collectively designated 23 couple the eccentrics 22 to the die holder 15 for imparting thereto rectilinear movement in a vertical direction.

The connecting means 23 comprise connecting rods 25 (FIG. 2) joined by first pivot pins 26 to respective links 27 which are coupled to the die holder 15 by second pivot pins 28. The links 27 respectively incorporate turn buckles 30 which provide adjustment for the shut height of the machine, that is, the terminal position of the die holder 15.

The frame 11 has coupled to it a pair of trunnion mounted hydraulic cylinders 32, one on the inner face of each of the end plates of the frame 11, the hydraulic cylinders 32 also being coupled to the connecting means 23.

The connecting means 23 further include guide arms 34 (FIG. 2) the guide arms 34 each containing a slot having parallel walls 35 which form guide tracks, the guide tracks guiding a roller 36 which is journalled on the first pivot pin 26 in each instance. Each guide arm 34 has a ramp roller 38 on a downward extension, the roller 38 engaging a ramp 39 which is pivoted on the end plate of the frame 11. Each guide arm 34 also is provided with an abutment projection 40 which is best seen in FIG. 7.

A front plate 43 of the frame 11 supports a pair of circular plates 44 as shown in FIGS. 2,4 and 5, each circular plate 44 having an outstanding flange 45 which engages a plurality of circumferentially spaced rollers 46, the flange 45 having its side faces engaged by respective retaining plates 47 which are bolted to the front plate 43 and which themselves carry the rollers 46. The flange 45 then resists displacement of its circular plate 44 in an axial direction.

Each circular plate 44 is provided with adjustable stop means comprising eight abutment plungers 50, each abutment plunger being slidable in a respective aperture in its plate 44, and being retained against rotation by means of a key 51, the abutment plungers each machine is required as for nibbling for example, the operating shaft 18 has secured to it a boss 58 (FIGS. 3 and 4), the boss 58 containing a cam slot 59 which opens into its end face 60, the cam slot 59 being releasably engaged by a roller 61 which depends from a rocker arm 62 pivotally carried on a depending pin 63 which depends from a beam 64 which forms portion of the frame 11. The rocket arm 62 is coupled to a pair of pawls 66 (one only of which is illustrated in FIG. 4) by respective coupling links 67 and the arrangement is such that rocking of the rocker arm 62 about its depending pin 63 moves the pawls in a backward and forward motion. The pawls engage between adjacent abutment plungers as shown in FIG. 4, each pawl being carried on a swinging arm 68 and being prevented from rotation in one direction by a joining link 69 coupled to a second swinging arm 70 as illustrated in FIG. 4. A respective stop 71 limits movement of the pawls 66 so that during indexing, rotation of the circular plates terminates positively.

The boss 58 also has secured to it a switch cam 73 illustrated in FIGS. 3 and 4 which operates a switch 74 of the roller on arm type (limit switch).

Indexing is required only for cyclic operations, and to enable disengagement of the indexing mechanism, an indexing control arm 76 is journalled in the front plate 43 of the frame as shown in FIGS. 3 and 4, the indexing control arm 76 having joined to it a rear arm 77 which has an outstanding pin 78 thereon, the outstanding pin 78 bearing against an upstanding pin 79on the rocker arm 62, and a spring 80 couples the pin 79 to an anchor pin 81 on the rear face of the front plate 43, the spring 80 then retaining the pins 78 and 79 contiguous, and when the rear arm 77 is in the position shown in FIGS. 3 and 4, urges the roller 61 into the cam slot 59 of the boss 58. The cam slot 59 of course overcomes the effort exerted by the spring 80 to move the pin 79 away from the pin 78 as the roller 61 is forced out of the slot 59 upon rotation of the operating shaft 18. When however the indexing control arm 76 is swung over to the alternative position shown dotted in FIG. 3, the pin 78 drives against the pin 79 to retain the roller 61 out of engagement of the slot 59 so that cyclic operation does not occur. At the same time a cable 84 shown only in FIG. 3 and coupled to the switch 74 retracts the switch arm from operation by the switch cam 73.

FIG. 7 illustrates the hydraulic and electric circuits for the control of the primary motion by the hydraulic cylinders 32. For the sake of simplicity one only cylinder 32 is shown in FIG. 7, the other cylinder however being connected in parallel.

also containing a threaded aperture 52 threadably engaged by a screw member 53 which is rotational in the plate 44 and which has an outstanding head 54. The assembly of each plunger 50 with its screw member 53 constitutes a screw threaded stop which is engageable by the abutment projection 40 of a respective guide arm 34. It might be noted that FIG. 2 illustrates the guide arm 34 in a retracted position wherein the abutment projection 40 is moved away from the screw threaded stop, and when in this position the circular plate 44 may be rotated or indexed to position a further screw threaded stop into operative alignment with the abutment projection 40.

In order to achieve this indexing, which is a desirable feature of the invention when automatic cycling of the A pump 88 draws hydraulic fluid from a reservoir 89 and delivers it through a pressure relief valve 90 to a double actingsolenoid valve 91, the valve 91 having two solenoids designated 92 (up) and 93 (down), the solenoids imparting an axial movement to a spool 94 which is normally retained in a central or intermediate position (as illustrated) by centralising springs 95.

Considering the electric circuit as shown, power is introduced through power supply lines 98, one of which is coupled to one lead of each of the solenoids 92 and 93, the other power line going to a foot control switch 99 (see also FIG. 6), the foot control switch 99 being controlled by a foot pedal 100 and having a neutral position and two operative positions. In the operative position which is illustrated, power is delivered to a pressure switch 101 which is arranged to be nonnally closed but to be open only when pressure therein builds up to a high value. The power then passes from the pressure switch to the coil 93 (the down solenoid). The spool is then moved to the left and fluid pressure flows through the hydraulically releasable check valve 103 to the back of the cylinder 32 to drive the piston thereof outwardly and impart primary motion to the press. In so doing, any overflow from the check valve passes upwardly into the spool valve 91 through the conduit into the reservoir 89.

When the pressure reaches a high value, the pressure switch 101 opens circuits and the spool returns to a neutral position allowinghydraulic fluid on the upstream side of the check valve 103 to drain back into the reservoir. This is a safety device.

When the switch 99 is moved to the neutral position neither of the solenoids is energised, but when moved to the uppermost position, the up solenoid 92, is energised and the action of the cylinders 32 is reversed to lift the die holder 15. However the fluid flowing into the inner ends of the cylinder flows through the check valve 105 which is also provided with a pressure relief function in a reverse direction (pressure lifting the valve element from its seat, the valve being of a type similar to valve 109 but not hydraulically operated), so that upon further outward movement of the pistons from the cylinders 32 pressure on the underside of the pistons does not build up excessively. The fluid pressure at the inlet to the check valve 105 is also directed to a pressure release connection on check valve 103 thereby allowing reverse flow through check valve 103 and enabling fluid to be released from the back of the cylinder 32.

It is desirable that the pressure should be maintained as low as possible, and there is less pressure required when the connecting rods-25 and links 27 approach alignment. The ramp 39 is coupled to a pilot valve 107 having a piston 108 therein which displaces fluid into a pressure relief valve 109 containing a piston 110 arranged to compress a spring 111 in turn increasing the relief pressure of the valve 109 when the cylinders 32 are retracted, that is, in the position illustrated in FIG. 7. As the cylinders expand,.the ramp 39 is free to lift under pressure exerted by'its spring 113, in turn relieving the pressure on thespring 111 and reducing the pressure at'which the relief valve 109 will open.

What I claim is:

l. A press comprising a frame, a bolster on the frame, a movabledie holder, guide means between the movable die holder and the frame guiding and movabledie shaft, said'drive means comprising a clutch for imparting intermittent rotary motion to the operating shaft, a crank on the operating shaft, and connecting means coupling the crank to the movable die holder to impart thereto said rectilinear movement; said connecting means comprising a connecting rod joumaled on said crank, a link, a first pivot pin pivotally connecting one end of said link to said connecting rod, a second pivot pin connecting the other end of said link to the movable die holder; a hydraulic cylinder operatively connecting the frame and said connecting means; said crank and connecting means being so constructed and arranged that operation of said hydraulic cylinder imparts primary motion to the movable die holder and rotation of said shaft imparts secondary motion thereto;

stop means carried on said frame, and an abutment member on said connecting means engageable against the stop means to thereby limit primary motion of the die holder.

2. A press according to claim 1 wherein the stop means carried on the frame is adjustable relative to said abutment member to adjust the limit of said primary motion.

3. A press according to claim 1 wherein said connecting means further comprises a guide arm, a bearing in the guide arm journalled on the operating shaft for pivotal support of the guide arm, said abutment member being on the guide arm, said guide arm containing a slot having parallel walls forming guide tracks, and rollers carried by said first pivot pin engaging the parallel walls.

4. A press according to claim 1 wherein said connecting means further comprises a guide arm, a bearing in the guide arm journalled on the operating shaft for pivotal support of the guide arm, said abutment member being on the guide arm, said guide arm containing a slot having parallel walls forming guide tracks, and rollers carried by said first pivot pin engaging the parallel walls, said hydraulic cylinder being connected to the guide arm.

5. A press according to claim 2 wherein said adjustable stop means comprises an abutment plunger which is movable axially with respect to the frame and which is threadably engaged by an adjusting screw member to thereby adjustably position the abutment plunger to relative the frame.

6. A press according to claim 1 further comprising a plate carried on the frame, means on the frame supporting the plate for rotation about an axis, and a plurality of said stop means circumferentially spaced on the plate on a pitch circle having said axis as its centre.

7. A press according to claim 6 wherein said rotatable plate has an outstanding circular flange, and said means supporting the plate for rotation comprise rollers which engage said flange, and further comprising a pair of retention plates supporting the rollers for rotation and also engaging the side faces of the flange to resist ,axial displacement of the rotatable plate, and means firmly securing said retention plates to the frame.

8. A press according to claim 6 further comprising a boss secured to the operating shaft, the boss having an end face and a cylindrical face, the cylindrical face containing a cam slot which opens into the said end face, a rocker plate hinged to the frame, a roller on the rocker plate engaging the cam slot and end face upon rotation of the operating shaft, pawls engaging said stop means for effecting rotational indexing of said rotatable plates, and linkage mechanisms coupling the pawls and the rocker plate.

9. A press according to claim 6 further comprising a boss secured to the operating shaft, the boss having an end face and a cylindrical face, the cylindrical face containing a cam slot which opens into the said end face, a rocker plate hinged to the frame, a roller on the rocker plate engaging the cam slot and end face upon rotation of the operating shaft, pawls engaging said stop means for effecting rotational indexing of said rotatable plate, linkage mechanisms coupling the pawls and the rocker plate, a control lever pivoted on the frame, and means operatively coupling the control lever to the rocker plate, the control lever thereby being operable to position the roller out of register with the cam slot.

10. A press according to claim 1 further comprising a foot pedal pivoted on the frame, a two-way foot control switch coupled to the pedal, and a double solenoid valve coupled to the hydraulic cylinder, the solenoids of the valve being selectively energised by operation of the control switch to in turn control direction and operation of the hydraulic cylinder.

11. A press according to claim 10 further comprising a clutch control link coupled to the foot pedal.

12. A press according to claim 10 further comprising a cam secured to the operating shaft, and a cam switch secured to the frame and operated by the cam, said cam switch being in the electrical circuit of one of the solenoids of said double solenoid valve and arranged to energise that solenoid for a period of time during rotation of the operating shaft.

13. A press according to claim 3 further comprising a ramp, a pivot supporting the ramp from the frame for pivotal movement relative thereto, a roller carried on a said guide arm movable over a ramp surface on the ramp, a spring urging the ramp into engagement with the roller, a pilot valve having a pilot piston coupled to the ramp, and a hydraulically controlled pressure relief valve coupled to the pilot valve to be operated thereby to decrease pressure applied to the hydraulic cylinder as it approaches the end of its stroke which imparts said primary motion.

14. A press according to claim 10 further comprising a conduit extending between the solenoid valve and that end of the hydraulic cylinder'in which applied pressure returns the hydraulic cylinder to an initial position occupied before commencement of the primary motion stroke, said conduit containing a valve which allows free flow in the direction from the solenoid valve to the cylinder but restrains flow in a reverse direction to thereby retain fluid at pressure in said end of the cylinder. 

1. A press comprising a frame, a bolster on the frame, a movable die holder, guide means between the movable die holder and the frame guiding and movable die holder for rectilinear movement on the frame, an operating shaft, drive means connected to the operating shaft, said drive means comprising a clutch for imparting intermittent rotary motion to the operating shaft, a crank on the operating shaft, and connecting means coupling the crank to the movable die holder to impart thereto said rectilinear movement; said connecting means comprising a connecting rod journaled on said crank, a link, a first pivot pin pivotally connecting one end of said link to said connecting rod, a second pivot pin connecting the other end of said link to the movable die holder; a hydraulic cylinder operatively connecting the frame and said connecting means; said crank and connecting means being so constructed and arranged that operation of said hydraulic cylinder imparts primary motion to the movable die holder and rotation of said shaft imparts secondary motion thereto; stop means carried on said frame, and an abutment member on said connecting means engageable against the stop means to thereby limit primary motion of the die holder.
 2. A press according to claim 1 wherein the stop means carried on the frame is adjustable relative to said abutment member to adjust the limit of said primary motion.
 3. A press according to claim 1 wherein said connecting means further comprises a guide arm, a bearing in the guide arm journalled on the operating shaft for pivotal support of the guide arm, said abutment member being on the guide arm, said guide arm containing a slot having parallel walls forming guide tracks, and rollers carried by said first pivot pin engaging the parallel walls.
 4. A press according to claim 1 wherein said connecting means further comprises a guide arm, a bearing in the guide arm journalled on the operating shaft for pivotal support of the guide arm, said abutment member being on the guide arm, said guide arm containing a slot having parallel walls forming guide tracks, and rollers carried by said first pivot pin engaging the parallel walls, said hydraulic cylinder being connected to the guide arm.
 5. A press according to claim 2 wherein said adjustable stop means comprises an abutment plunger which is movable axially with respect to the frame and which is threadably engaged by an adjusting screw member to thereby adjustably position the abutment plunger relative to the frame.
 6. A press according to claim 1 further comprising a plate carried on the frame, means on the frame supporting the plate for rotation about an axis, and a plurality of said stop means circumferentially spaced on the plate on a pitch circle having said axis as its centre.
 7. A press according to claim 6 wherein said rotatable plate has an outstanding circular flange, and said means supporting the plate for rotation comprise rollers which engAge said flange, and further comprising a pair of retention plates supporting the rollers for rotation and also engaging the side faces of the flange to resist axial displacement of the rotatable plate, and means firmly securing said retention plates to the frame.
 8. A press according to claim 6 further comprising a boss secured to the operating shaft, the boss having an end face and a cylindrical face, the cylindrical face containing a cam slot which opens into the said end face, a rocker plate hinged to the frame, a roller on the rocker plate engaging the cam slot and end face upon rotation of the operating shaft, pawls engaging said stop means for effecting rotational indexing of said rotatable plates, and linkage mechanisms coupling the pawls and the rocker plate.
 9. A press according to claim 6 further comprising a boss secured to the operating shaft, the boss having an end face and a cylindrical face, the cylindrical face containing a cam slot which opens into the said end face, a rocker plate hinged to the frame, a roller on the rocker plate engaging the cam slot and end face upon rotation of the operating shaft, pawls engaging said stop means for effecting rotational indexing of said rotatable plate, linkage mechanisms coupling the pawls and the rocker plate, a control lever pivoted on the frame, and means operatively coupling the control lever to the rocker plate, the control lever thereby being operable to position the roller out of register with the cam slot.
 10. A press according to claim 1 further comprising a foot pedal pivoted on the frame, a two-way foot control switch coupled to the pedal, and a double solenoid valve coupled to the hydraulic cylinder, the solenoids of the valve being selectively energised by operation of the control switch to in turn control direction and operation of the hydraulic cylinder.
 11. A press according to claim 10 further comprising a clutch control link coupled to the foot pedal.
 12. A press according to claim 10 further comprising a cam secured to the operating shaft, and a cam switch secured to the frame and operated by the cam, said cam switch being in the electrical circuit of one of the solenoids of said double solenoid valve and arranged to energise that solenoid for a period of time during rotation of the operating shaft.
 13. A press according to claim 3 further comprising a ramp, a pivot supporting the ramp from the frame for pivotal movement relative thereto, a roller carried on a said guide arm movable over a ramp surface on the ramp, a spring urging the ramp into engagement with the roller, a pilot valve having a pilot piston coupled to the ramp, and a hydraulically controlled pressure relief valve coupled to the pilot valve to be operated thereby to decrease pressure applied to the hydraulic cylinder as it approaches the end of its stroke which imparts said primary motion.
 14. A press according to claim 10 further comprising a conduit extending between the solenoid valve and that end of the hydraulic cylinder in which applied pressure returns the hydraulic cylinder to an initial position occupied before commencement of the primary motion stroke, said conduit containing a valve which allows free flow in the direction from the solenoid valve to the cylinder but restrains flow in a reverse direction to thereby retain fluid at pressure in said end of the cylinder. 